a) Field of the Invention
The present invention relates to a semiconductor wafer termed with a plurality of chip areas each having integrated circuits (ICs) or (large scale integrated circuits (LSIs).
b) Description of the Related Art
On a semiconductor wafer formed with a plurality of chip areas each having ICs and LSIs, there are formed, in addition to patterns of chips, test element groups (TEG) having various test elements on scribe lines for dicing the semiconductor wafer into semi conductor chips by using a dicing apparatus, TEG being used for testing the performance of basic elements and the quality of manufacturing processes.
Most of the test elements constituting TEG have a size of 50 to 100 .mu.m square. Some test elements have various configurations similar to basic elements. However, most of the test elements includes test electrodes 1 shown in FIG. 6 having a simple rectangle allowing a probe contact for electrical measurement. In FIG. 6, reference numeral 2 represents a scribe line, and reference numeral 3 represents a passivation film.
The test electrodes 1 and other test elements formed on the scribe lines 2 are eventually cut by a dicing apparatus from the upper portion of the wafer above a dicing margin 4, as shown in FIGS. 7A and 7B. FIG. 7A is a plan view, and FIG. 7B is a cross sectional view taken along line VIIB--VIIB of FIG. 7A.
The width of the scribe Nine 2 is generally 100 .mu.m more or less. The width of the dicing margin 4 is generally 30 .mu.m more or less. In FIGS. 7A and 7B, reference numeral 5 represents an insulating film, reference numeral 6 represents silicon substrate, and reference numeral 7 represents a curled metal piece ready to be pealed off.
As the semiconductor wafer is diced by a dicing apparatus, the dicing margin 4 of the test electrode 1 traverses along the central area of the electrode 1 separating it.
In many cases, the test electrode 1 on the scribing margin 4 remains as metal pieces 7 on the semiconductor chip surface without being fully scribed. The metal pieces 7 are removed from the semiconductor surface at the succeeding process including a washing process at the dicing process.
Even after the succeeding process, some metal pieces 7 of the test electrode 1 remain on the upper edge of a semiconductor chip. Such a metal piece has a small diameter and width in the order of 10 .mu.m, but the length thereof is as long as the length (50 to 100 .mu.m) of the test electrode at a maximum.
Such a long metal piece 7 may be pealed off at the succeeding process such as the assembly process of plastic molding, in the shape off a metal piece 8 such as shown in FIG. 8, and mixed into the mold.
Since this metal piece 8 is as long as 50 to 100 .mu.m, it may enter between IC or LSI pins, bonding pads, or the like, respectively spaced apart only by a distance 50 to 70 .mu.m, and short-circuit these pins or pads.